Extension beam for compasses



April 13 1926."

Fil ed March 22 magi Patented Apr. 13, 1926.

UNITED STA S HUGO PRUSS, 0F BERKELEY, CALIFORNIA.

EXTENSION BEAM FOR COMPASSES.

Application filed March 22', 1923. SeriaI'No. 626,772.

To all whom it may concern:

Be it known that I, I-IUoo Faces, a citizen of Peru, residing at Berkeley, in the county of Alameda and State of California, have invented new and useful Improvements in Extension Beams for Compasses, of which the following is a specification.

This invention relates to scientific instruments,'and more particularly to extension beams for compasses.

It is an object of the present invention to provide an extension beam to which engineers or draftsmens compasses may be read ily attached so as to facilitate the scribing of curves having a length greater than the ordinary range of extended compasses as ordinarily provided in drafting sets. A broad object of the invention is to provide means for utilizing dividers and compasses as commonly provided in drawing instrument sets and also to overcome the necessity of special trammel parts.

An object is to provide an extension beam of simple and substantial construction and which provides for a reasonable degree of adjustment to vary the length of radii. Also, an object is to provide an extension compass beam which will enable the attachment of an ordinary compass and provide for variation of length of radius by movement of one of the compass legs while the compass is adapted to the beam.

An object is to provide a drawing instrument including a beam to which may be firmly attached as a pivot one leg of a divider and to which beam may be attached one leg of a compass, the opposite leg of which is adjustable and serves as the scribing point.

Other objects and advantages will be made manifest in the following specification of an embodiment of the invention illus-' accompanying drawings,

is provided with a fork or longitudinally slotted end, thus forming opposed resilient jaws 3 and t transversely through -which pass a clamp screw Storming one means by which the yielding ends of the jaws may be contracted so as to bind upon and securely hold an interposed leg of a divider or compass C. The opposite leg of the compass C forms the center when applied to a surface about which the beam can be swung in scribmg, or may form the scribing means.

Slidably mounted upon the beam 2 is a slide or box 6 in which is arranged a shoe 7 between which and one side of the box there is disposed a spring 8, and this in turn may be engaged by an adjusting screw 9 whereby the shoe can be firmly set against the side of the beam to hold the slide in any of its positions along the beam. The ends of the shoe 7 are bent outwardly to engage the ends of the box 6, so that when the box is moved along the beam the shoe will surely go with the box. The slide is provided with means in which may be adjusted and clamped a compass or divider C, preferably the clamped leg of which is disposed vertically or perpendicularly as to the axis of the beam 2, as clearly shown in Figure 1, while the clamped leg of the compass or divider C in the opposite end of the beam is secured obliquely as to the axis of the beam.

The con'ipass-clan'iping means carried by the slide may consist of a block or bar 10 bifurcated longitudinally and forming clamping jaws 11 and 12 adapted to be clamped by a screw 13 on the interposed leg of a compass C. The springing ends of the clamp jaws 11 and 12 are shown. as end ing perpendicularly to the length of the block 10 and are beveled or converged inwardly so as to facilitate the introduction of the compass leg which is clamped in effective position perpendicularly, as shown in Figure 1, close to the screw 12. The clamping aws 3 and d of the opposite end of the beam are cut angularly at their ends 3 to the axis of the beam and thus form a guide to indicate the proper position of the leg of a divider or compass C, as in Figure 1. The angular adjustment of one leg of the compass in the jaws 3 and 4 thus provides for a substantially perpendicular position of the opposite leg of the compass.

In operation of the device, the dividers or compasses, as the case may be, are clamped in the respective parts and the slide 10 is adjusted along the beam 2 to the approximate position determining the distance between the center-formingleg and the scribing leg of the combined instrument. A reasonable amount of variation may be accomplished by the movement of the swinging leg of the divider or compass C and further variation and adjustment may be secured by sliding the box or slide 6 along the beam; this being made without angular adjustment of either of the legs of the divider or compass C in the clamp device 10.

It will be understood that the instrument can be utilized with either metal scribing points or pencil scribing or ink scribing means.

Further embodiments, modifications and variations may be resorted to within the principle of the invention.

What is claimed is:

In an extension beam construction, a beam, a box slidably mounted upon the beam, a shoe in, the box against one side of the beam and held to slide with the box, a spring in the box against the shoe a screw tapped through the box against the spring, a block bifurcated from one end with one jaw fitting in the box against the other side of the beam from the shoe, and a clamping screw in the block crosswise 01" the bifurcation near its open end.

In testimony whereof I have signed my name to this specification.

HUGO PRUSS. 

